Riyad S. Aboutaha, PhD, F -ACI Associate Professor Syracuse University

1. Actions and Retrofit of Post Earthquake-Damaged Bridges Riyad S. Aboutaha, PhD, F-ACI Associate Professor Syracuse University Albany, NY Sept. **, 2010 NYSDOT Syracuse University University at Buffalo

2. GENERAL OUTLINE • Introduction and Classification of Post-EQ Repair • Post-EQ Retrofit of Bridge Elements • Field Guide for Post-EQ Retrofit of Bridge Elements • Summary and Conclusions

3. INTRODUCTION and CLASSIFICATION • OBJECTIVE • Provide field inspectors and engineers with a quick guide for post-earthquake retrofit of bridges • CLASSIFICATIONS • Immediate Action / Retrofit • Short-Term Retrofit • Long-Term Retrofit

4. INTRODUCTION and CLASSIFICATION • IMMEDIATE ACTION/RETROFIT • Intended to stabilize the bridge and reduce the likelihood of further damage or progressive collapse, particularly during after-shocks • Make the site safer for safer for further detailed inspection and retrofit

5. INTRODUCTION and CLASSIFICATION • SHORT-TERM RETROFIT • Intended to make the bridge safer for light emergency traffic (police cars, and ambulances, etc.), heavy emergency traffic (fire trucks) at limited speed, or allow ALL traffic. • Immediate and short term retrofits may overlap, where the immediate-retrofit may serve as short-term retrofit.

6. INTRODUCTION and CLASSIFICATION • LONG-TERM RETROFIT • Intended to restore the bridge to its original strength, and possibly strengthen the bridge to improve its seismic resistance • It may involve detailed seismic analysis of the bridge, as well as detailed design of the retrofit system by a structural engineer

7. INTRODUCTION and CLASSIFICATION Deck Failure

8. INTRODUCTION and CLASSIFICATION Superstructure Joint Failure

9. INTRODUCTION and CLASSIFICATION Pounding Damage

10. INTRODUCTION and CLASSIFICATION Column Damage (Flexure / Shear)

11. INTRODUCTION and CLASSIFICATION Column Failure

12. INTRODUCTION and CLASSIFICATION

13. INTRODUCTION and CLASSIFICATION • BASIC ASSESSMENT • Identify the purpose of the element /sub-element • SHEAR FAILURE • Purpose of stirrups • Resist shear • Confine column • Prevent buckling of longitudinal bars

14. POST-EQ RETROFIT OF BRIDGES • MATERIALS • Steel: structural shapes, prestressing strands/bars, plates, and cables. • Fiber Reinforced Polymer (FRP) Composite • Polymer concrete • Polymer modified concrete / Non-shrink Grout • Special tools: flat jacks, chains, etc.

15. POST-EQ RETROFIT OF BRIDGES Application of External Prestressing strands/bars External Post-tensioning

16. POST-EQ RETROFIT OF BRIDGES Application of Structural shapes/cables

17. POST-EQ RETROFIT OF BRIDGES Application of Structural Steel Plates 1.0 inch thick non-shrink grout Min. ½” thick Steel jacket Uniform Confining Pressure Steel jacketed circular column Uniform confining pressure produced by circular steel jacket

18. POST-EQ RETROFIT OF BRIDGES Application of Structural Steel Plates 4.0” long steel angle with hole for assembly of steel shells spaced 3 feet center-center Steel bolt Assembly detail of a circular steel jacket

19. POST-EQ RETROFIT OF BRIDGES Application of Structural Steel Plates Steel back plate for field welding. It is welded to one steel shell in shop, and field welded to the other shell. Details of the circular steel jacket’s shells

20. POST-EQ RETROFIT OF BRIDGES Application of Structural Steel Plates Non-Uniform Confining Pressure Shear retrofit of rectangular column section using rectangular steel jacket Non-uniform confining pressure produced by rectangular steel jacket

21. POST-EQ RETROFIT OF BRIDGES Application of Structural Steel Plates Lap splice retrofit of rectangular column section using elliptical steel jacket

22. POST-EQ RETROFIT OF BRIDGES FRP Diagonal anchor (a) Straight FRP sheet along with diagonal FRP anchors. Application of FRP Composites

23. POST-EQ RETROFIT OF BRIDGES Application of FRP Composites Uniaxial Diagonal FRP anchor Uniaxial FRP Composite strip/sheet (b) Isometric view of a strengthened beam with straight FRP system on the tension side, along with diagonal FRP anchors.

24. POST-EQ RETROFIT OF BRIDGES Application of FRP Composites Uniform Confining Pressure FRP repaired circular column section Uniform confining pressure produced by circular FRP jacket

25. POST-EQ RETROFIT OF BRIDGES • Approach Roadways • Bridge Decks • Bridge Abutments • Bridge Piers and Column • Bridge Girders • Foundation

26. POST-EQ RETROFIT OF BRIDGES • Retrofit of Damaged Approach Roadway • In general, the level of damage is classified based on amount of settlement • For minor settlement (d<2”), it is not a critical structural damage, however, it may pose serious driving hazard, that may affect traffic safety (use warning signs) • For major settlement (d>6”), must check abutment and its wing walls • Retrofit: refilled/repaved

27. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Approach Roadways

28. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Decks Minor Moderate Severe

29. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Decks

30. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Abutment EQ

31. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Abutment

32. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Pier Columns Typical Seismic Deficiencies

33. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Pier Column (Shear Failure) Minor Severe

34. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Pier Column (Shear Failure)

35. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Pier Columns Typical Seismic Deficiencies

36. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Pier Column (Flexural Failure) Minor Severe

37. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Bridge Pier Column (Flexural Failure)

38. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Prestressed Concrete Girders

39. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Steel Girders

40. POST-EQ RETROFIT OF BRIDGES Foundation Failure (b) Shear Failure (c) Anchorage Failure (a) Pile Overload (d) Pile Pullout (e) Rebar Flexural Yielding (f) Pile Shear Failure

41. POST-EQ RETROFIT OF BRIDGES Retrofit of Damaged Foundation • Check Deformations (rotation, level), and concrete distress • Requires extensive structural evaluation and retrofit measures

42. Strategiespage 1

43. Strategiespage 2

44. Summary & Conclusions • Good understanding of the behavior of bridge elements helps identify the load path, and consequently the best retrofit system to ensure the continuity of the load path • A retrofit system is intended to serve the role of the damaged element or sub-element • Pay attention to the overall stability of the bridge system • Last but not least: SAFETY COMES FIRST!

45. THANK YOU!